Coffee machine



FIG. 1 is a top, front, and left side perspective view of a coffee machine showing my new design;

FIG. 2 is a right side elevational view thereof;

FIG. 3 is a top plan view thereof; and,

FIG. 4 is a bottom plan view thereof.

The undisclosed rear of the coffee machine is conventional in appearance. 

The ornamental design for a coffee machine, as shown and described. 